A Comprehensive Monitoring System for Online Fault Diagnosis and Aging Detection of Non-Isolated DC–DC Converters’ Components

Online monitoring is an inevitable necessity for dc-dc converters in industrial applications to achieve a fault-tolerant structure, which ensures reliable operation and prevents catastrophic failures. In this paper, a comprehensive monitoring system is proposed for non-isolated dc-dc converters. The proposed approach is mainly focused on monitoring the most prone to failure components of these converters including switching devices and capacitor. Using the proposed monitoring system, switch/diode open circuit and short circuit faults are detected in less than one switching cycle. Furthermore, online monitoring of the capacitor equivalent series resistance and switch on-state voltage as effective precursors of aging is also carried out. Finally, an inter-turn fault detection technique is presented for the converter inductor. The mentioned monitoring tasks are accomplished using only two electrical sensors (for capturing voltages across the converter diode and inductor) and two temperature sensors. The presented monitoring approach is simple, cost-effective, easy to implement, and applicable for all non-isolated dc-dc converters including buck, boost, and buck-boost converters. Performance of the monitoring system is evaluated by considering different scenarios in the experiments carried out on a laboratory prototype. The results confirm the effectiveness of the proposed system for fault diagnosis and aging monitoring in non-isolated dc-dc converters.